A library to easily extract unified metadata from websites using Open Graph, Microdata, RDFa, Twitter Cards, JSON-LD, HTML, and more.
What is it
The metascraper library allows you to easily scrape metadata from an article on the web using Open Graph metadata, regular HTML metadata, and a series of fallbacks.
It follows a few principles:
- Ensure a high accuracy for online articles by default.
- Make it simple to add new rules or override existing ones.
- Don’t restrict rules to CSS selectors or text accessors.
Getting started
Below is a real example of extracting metadata from a live website. The same logic shown here is running online and can be tested directly at microlink.io/meta:
metascraper requires two inputs: The target URL and the HTML markup behind that URL.
There are multiple ways to retrieve the HTML markup, but it needs to be as accurate as possible.
For that reason, we developed html-get, which uses a headless browser to retrieve HTML in a way that works seamlessly with metascraper.
const getHTML = require('html-get')
const browserless = require('browserless')()
const getContent = async url => {
const browserContext = browserless.createContext()
const promise = getHTML(url, { getBrowserless: () => browserContext })
promise.then(() => browserContext).then(browser => browser.destroyContext())
return promise
}
const metascraper = require('metascraper')([
require('metascraper-author')(),
require('metascraper-date')(),
require('metascraper-description')(),
require('metascraper-image')(),
require('metascraper-logo')(),
require('metascraper-publisher')(),
require('metascraper-title')(),
require('metascraper-url')()
])
getContent('https://microlink.io')
.then(metascraper)
.then(metadata => console.log(metadata))
.then(browserless.close)
.then(process.exit)
The output will be something like:
{
"author": "Microlink HQ",
"date": "2022-07-10T22:53:04.856Z",
"description": "Enter a URL, receive information. Normalize metadata. Get HTML markup. Take a screenshot. Identify tech stack. Generate a PDF. Automate web scraping. Run Lighthouse",
"image": "https://cdn.microlink.io/logo/banner.jpeg",
"logo": "https://cdn.microlink.io/logo/logo.png",
"publisher": "Microlink",
"title": "Turns websites into data — Microlink",
"url": "https://microlink.io/"
}
What data it detects
Note: Custom metadata detection can be defined using a rule bundle.
Here is an example of the metadata that metascraper can detect:
-
audio — e.g. https://cf-media.sndcdn.com/U78RIfDPV6ok.128.mp3
A audio URL that best represents the article.
-
author — e.g. Noah Kulwin
A human-readable representation of the author’s name.
-
date — e.g. 2016-05-27T00:00:00.000Z
An ISO 8601 representation of the date the article was published.
-
description — e.g. Venture capitalists are raising money at the fastest rate…
The publisher’s chosen description of the article.
-
video — e.g. https://assets.entrepreneur.com/content/preview.mp4
A video URL that best represents the article.
-
image — e.g. https://assets.entrepreneur.com/content/3x2/1300/20160504155601-GettyImages-174457162.jpeg
An image URL that best represents the article.
-
lang — e.g. en
An ISO 639-1 representation of the url content language.
-
logo — e.g. https://entrepreneur.com/favicon180x180.png
An image URL that best represents the publisher brand.
-
publisher — e.g. Fast Company
A human-readable representation of the publisher’s name.
-
title — e.g. Meet Wall Street’s New A.I. Sheriffs
The publisher’s chosen title of the article.
-
url — e.g. http://motherboard.vice.com/read/google-wins-trial-against-oracle-saves-9-billion
The URL of the article.
The cloud API solution
Running this at scale means operating headless browsers, proxies, and antibot workarounds.
If you don’t want to manage that infrastructure, you can use the fully managed
Microlink API.
It automatically handles proxy rotation, paywalls, bot detection, and restricted platforms such as major social networks, while scaling on demand.
Pricing is pay-as-you-go and starts for free.
How it works
metascraper is built out of rules bundles.
It is designed to be extensible. You can compose your own transformation pipeline using existing rules or create your own.
Rule bundles are collections of HTML selectors targeting a specific property. When you load the library, it implicitly loads the core rules.
Each set of rules loads a set of selectors to extract a specific value.
Rules are ordered by priority. The first rule to successfully resolve the value stops the process. The order goes from most specific to most generic.
Rules work as fallbacks for one another:
- If the first rule fails, then it falls back on the second rule.
- If the second rule fails, it is time for the third rule.
- Etc.
metascraper does this until it finishes all the rules or finds the first rule that resolves the value.
Importing rules
metascraper exports a constructor that need to be initialized providing a collection of rules to load:
const metascraper = require('metascraper')([
require('metascraper-author')(),
require('metascraper-date')(),
require('metascraper-description')(),
require('metascraper-image')(),
require('metascraper-logo')(),
require('metascraper-publisher')(),
require('metascraper-title')(),
require('metascraper-url')()
])
Again, the order of rules are loaded are important: Just the first rule that resolve the value will be applied.
Use the first parameter to pass custom options specific per each rules bundle:
const metascraper = require('metascraper')([
require('metascraper-logo')({
filter: url => url.endsWith('.png')
})
])
Rules bundles
?> Can’t find the rules bundle that you want? Let’s open an issue to create it.
Official
Rules bundles maintained by metascraper maintainers.
Core essential
Vendor specific
Rules bundles maintained by individual users.
See CONTRIBUTING to add your own module!
API
constructor(rules)
Create a new metascraper instance declaring the rules bundle to be used explicitly.
rules
Type: Array
The collection of rules bundle to be loaded.
Call the instance for extracting content based on rules bundle provided at the constructor.
options
html
Type: String
The HTML markup for extracting the content.
htmlDom
Type: object
The DOM representation of the HTML markup. When it’s not provided, it’s get from the html parameter.
omitPropNames
Type: Set
Default: []
A set of property names that should be omitted. When specified, these properties will be missing in the returned metadata objects, and rules related to that will not be computed.
pickPropNames
Type: Set
Default: undefined
A set of property names to pick for the metadata extraction process. When specified, only rules for these properties will be executed, and all other properties will be omitted. Takes precedence over omitPropNames when both are specified.
rules
Type: Array
You can pass additional rules to add on execution time.
These rules will be merged with your loaded rules at the beginning.
url
Required
Type: String
The URL associated with the HTML markup.
It is used for resolve relative links that can be present in the HTML markup.
it can be used as fallback field for different rules as well.
validateUrl
Type: boolean
Default: true
Ensure the URL provided is validated as a WHATWG URL API compliant.
const metascraper = require('metascraper')([
require('metascraper-title')(),
require('metascraper-image')(),
require('metascraper-description')()
])
const html = '<title>Example</title><meta property="og:image" content="image.jpg">'
const url = 'https://example.com'
const omitPropNames = new Set(['image'])
const metadata = await metascraper({ url, html, omitPropNames })
console.log(metadata)
Environment Variables
Type: boolean
Default: true
It attemptt to load re2 to use instead of RegExp.
Benchmark
To demonstrate metascraper’s exceptional accuracy, here is how it outperforms similar libraries:
A big part of the reason for metascraper’s higher accuracy is that it relies on a series of fallbacks for each piece of metadata, instead of just looking for the most commonly-used, spec-compliant pieces of metadata, like Open Graph.
metascraper’s default settings are targetted specifically at parsing online articles, which is why it’s able to be more highly-tuned than the other libraries for that purpose.
If you’re interested in the breakdown by individual pieces of metadata, check out the full comparison summary, or dive into the raw result data for each library.
License
metascraper © Microlink, released under the MIT License.
Authored and maintained by Microlink with help from contributors.
microlink.io · GitHub microlinkhq · X @microlinkhq
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